I have two session beans in the app I am developing that need hour or two hour long transaction times, so I code those with bean managed transaction stateless session beans.
The other stateless session beans, that have container managed transactions, use the global default of 300 seconds.
Please read carefully what I've written above. My problem is not a transaction timeout (which I know how to deal with). My problem is out of memory due to instantiation and wrong(?) passivation of thousands entity beans. I described the problem in detail in my previous post.